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Beddomeia minima Petterd, 1889

Diagnostic features

Species of the B. hullii group are found in the northern half of Tasmania. Their shells are small (1.7-3.7 mm in length; most less than 3.5 mm), simple, ovate-conic to broadly conic, with a thin inner lip and no columellar bulge. The periphery of the last whorl of the shell is rounded, subangled or angled and the penis simple.

The relationships of this species are not entirely clear-cut as the type locality is vague and material identical to the types has not been dissected. Similar specimens (B. cf. minima of Ponder et al. (1993) have the bursa duct and oviduct joining at the posterior pallial wall, not in front of it as in other similar species.

Classification

Beddomeia minima Petterd, 1889

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha

Superfamily Truncatelloidea

Family Tateidae

Genus Beddomeia Petterd, 1889

Original name: Beddomeia launcestonensis var. minima Petterd, 1889. Petterd, W. F. (1889). Contributions for a systematic catalogue of the aquatic shells of Tasmania. Papers and Proceedings of the Royal Society of Tasmania 1888: 60-83.

Type locality: Scottsdale, Tasmania.

State of taxonomy

The status of this species is not entirely clear as the original locality is not precise and whether or not it is still extant in that location is unknown.

Biology and ecology

On all substrates - leaves, stones, wood in stream. Egg capsules presumably like those of other species of Beddomeia - dome-shaped, with broad attachment base, covered with minute, mainly white sand grains and other fragments and containing a single egg. Development direct.

Distribution

Scottsdale and unnamed tributary of St. Patricks River, Tasmania.

Notes

All species of Beddomeia are geographically isolated and have restricted ranges.

This species is on the Tasmanian Threatened species list of Invertebrate Animals as Rare (small population at risk).

Further reading

Petterd, W. F. (1889). Contributions for a systematic catalogue of the aquatic shells of Tasmania. Papers and Proceedings of the Royal Society of Tasmania 1888: 60-83.

Ponder, W. F., Clark, G. A., Miller, A. C. & Toluzzi, A. (1993). On a major radiation of freshwater snails in Tasmania and eastern Victoria: a preliminary overview of the Beddomeia group (Mollusca: Gastropoda: Hydrobiidae). Invertebrate Taxonomy 7: 501-750.